Eat Memory. In C. For testing memory limits.

eatmem.c

// Compile with e.g. `gcc -o /tmp/eatmem /tmp/eatmem.c`

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#define DEFAULT_SLEEP_SECONDS 600
#define DEFAULT_ALLOC_MB 1024

int main(int argc, char **argv) {
  void *p, *end, *cur;
  size_t megs;
  const size_t one_meg = 1024 * 1024;
  const size_t page_size = 4096;
  unsigned int sleep_secs = DEFAULT_SLEEP_SECONDS;

  if (argc == 1) {
    megs = DEFAULT_ALLOC_MB;
    printf("Using defaults. Specify some different with `%s <megs>`.\n",
           argv[0]);
  } else {
    megs = atoi(argv[1]);
  }
  printf("Reserving %luM and touching in steps of %hu.\n", (unsigned long)megs,
         (unsigned short)page_size);

  char *sleep_timeout;
  sleep_timeout = getenv("SLEEP_TIMEOUT");
  if (sleep_timeout != NULL) {
    int sleep_secs_tmp = atoi(sleep_timeout);
    sleep_secs = (sleep_secs_tmp > 0) ? sleep_secs_tmp : sleep_secs;
  }
  printf(
      "this program will sleeep for %u seconds after memory allocation done.\n",
      sleep_secs);

  p = calloc(megs, one_meg);
  if (!p) {
    perror("calloc()");
    exit(EXIT_FAILURE);
  }
  end = p + megs * one_meg;
  for (cur = p; cur < end; cur += page_size) {
    *(char *)cur = 0xAA;
  }

  sleep(sleep_secs);
  free(p);
  printf("done and exit\n");
  exit(EXIT_SUCCESS);
}